Before I begin to shape raglans, how do I increase the length without throwing the stitch count off when I begin to shape the raglans? Won't I have to add more than the 3 sts I added at the beginning in order for the sleeve to be shaped properly as I increase the length? If so, how/where do I increase in the ribbed sleeve pattern and how/where do I decrease in ribbed pattern when I begin to shape the raglan so I end up with 68 sts (in the first two rows of shaping) so I can continue per the original pattern?

I agree with GG. You would normally increase 3sts and knit the second rib pattern up to the raglan shaping (aproximately at the underarm). I don't see why you can't continue for the 3 extra inches that you want. This rib doesn't have any increases in it as written. I assume the pattern has already taken the width of the sleeve into account in the second rib pattern. If that width is ok for you, then just extend the second rib.

I agree with GG. You would normally increase 3sts and knit the second rib pattern up to the raglan shaping (aproximately at the underarm). I don't see why you can't continue for the 3 extra inches that you want. This rib doesn't have any increases in it as written. I assume the pattern has already taken the width of the sleeve into account in the second rib pattern. If that width is ok for you, then just extend the second rib.

Thank you. I appreciate your advice and GG's! The reason I thought I had to continue to add stitches every inch or so was because I made a raglan t-shirt that added a stitch on either side of the row about every inch for three inches. This added 6 extra stitches before starting the raglan sleeve shaping. After studying the raglan t-shirt pattern, I just assumed all sleeves for all patterns would have to be shaped and have stitches added in the same way. As you can tell, I'm a novice at this! Thanks again!

Most sleeves are shaped as you describe but every now and then you come upon some that aren't. See how wide the sleeve is as you knit (or calculate the width from a gauge swatch in the rib pattern) to make sure the sleeves won't be too tight.